The present invention relates to an image display faceplate on which conductive organic polymeric transparent anti-static film is formed, its solution and its manufacturing method, and in detail to an image display faceplate coated by a conductive organic polymeric film having the improved anti-static characteristics, and adaptive to prevent the reflectivity of an ambient light source, on the exterior surface of the faceplate panel, and more particularly to image display faceplate on the exterior surface of which a transparent anti-static film is formed with conductive organic polymers, and to the coating solution and the manufacturing method of coating the faceplate therewith.
Recently, wide use of an anti-explosion type cathode ray tube has made a face cover glass unnecessary in a television receiver, a monitor, etc., for the prevention of electrostatic charge, thereby exposing the front portion of the cathode ray tube and giving electric shock by charged electrical high voltage to a person who comes in contact with the faceplate of the cathode ray tube. Furthermore, dust in air particles, etc., adhere to and accumulate on the charged faceplate of the cathode ray tube, so that the image on the display faceplate is difficult to see.
The cause of electrostatic charge as to the faceplate panel is as follows.
A thin and uniform aluminium film is deposited by vacuum on the phosphor screen structure on the interior surface of the faceplate panel. When a electric power is applied to, a high anode voltage is applied to the aluminium film. Electric charges generate on the exterior surface wall of the panel by electrostatic induction due to the high voltage of the inside aluminium film.
Korean patent publication No. 2713 is prior art for providing anti-static characteristics on an image display faceplate, and describes one such anti-static coating formed by the steps of preparing a slurry by mixing an alcohol solution containing alkoxysilane Si(OR)4 (where R is an alkyl group) and at least one of tin oxide, indium oxide, and antimony oxide, spraying the slurry on the faceplate panel, and heat-treating the sprayed panel at a relatively low temperature.
U.S. Pat. No.5,750,054, issued to Patrizia Cinquina, Vasto, et al. on May 12, 1998, discloses an anti-static, anti-glare coating for a reflective-transmissive surface wherein the surface is applied onto with a coating solution comprising a thiophene-based, electroconductive polymer and a siliceous material. As the concrete electroconductive polymer, polyethylenedioxythiophene, and as a siliceous material, lithium-stabilized silica sol and tetraethoxysilane are disclosed.
However, the metallic oxide costs too much, thereby making the manufacturing cost very high.
Further, the problem is that while the metallic oxide exists dispersedly in the alcohol solution, deposition problem arises due to cohesion between the particles according the condition of the surroundings, thereby making spots or unevenness.
Accordingly, it is one object of the present invention to provide an image display faceplate and its manufacturing method wherein an electroconductive organic polymeric transparent anti-static film is formed on the image display faceplate by the steps of obtaining an aqueous solution by dissolving electroconductive organic polymers in water, applying the solution and heat-treating the applied faceplate panel and the solution at a relatively low temperature.
To accomplish the aforementioned purpose, the present invention provides an electroconductive organic polymeric solution for application onto an image display faceplate in order to form an electroconductive, anti-static film on its exterior surface, said solution being prepared by the steps of: dissolving in alcohol an aqueous solution of polyethylene dioxythiophene doped with polystyrene sulphonate, then adding silicon alkoxide to the alcoholic solution, and finally adding pure water and an inorganic acid catalyst for hydrolysis.
Polystyrene sulphonate, sometimes referred to as polystyrene sulfonate, is an alkyl salt manufactured by sulfonating a polystyrene (e.g., adding SO3H to a polystyrene) and then neutralizing the resulting compound. Polystyrene sulphonate is shown below: 
Polystyrene sulphonate is represented by the chemical formula [xe2x80x94CH2CH (C6H4SO3HOxe2x80x94].
Also, the present invention provides an image display a faceplate on which conductive organic polymeric transparent anti-static film is formed on the exterior surface, said film being formed by dissolving in alcohol an aqueous solution of polyethylene dioxythiophene doped with polystyrene sulphonate, then adding silicon alkoxide to the alcoholic solution, then adding pure water and an inorganic acid catalyst for hydrolysis, and applying the resultant electroconductive organic polymeric solution onto the faceplate.
In a method of manufacturing the image display faceplate, on its exterior surface of which an electroconductive, anti-static film is formed, the method comprises the steps of applying the electroconductive organic polymeric solution onto the exterior surface of the faceplate by means of one or the combination of spin-coating spraying and dipping, and heat-treating the applied faceplate at a relatively low temperature between 150 and 180 degrees centigrade.
It is preferred that the electroconductive organic polymeric solution contains polyethylene dioxythiophene of 0.01 to 0.65 wt. % as a solid portion, doped with polystyrene sulphonate, 40 to 90 wt. % of at least one of alcohol in which the number of carbon atoms is between 1 to 10, and silicon alkoxide of 1 to 10 wt. %.